Atomizer spring



Dec. 7,1926. l 1,609,578

P. L. SCOTT ATOMIZER SPRING Filed August 8, 1921' Inf/6722507" PatentedDec. 7, 1926.

1,609,518 UNITED STATES PATENT? OFFICE.

:PHILIP LANE sCOTT, OF CHICAGO, ILLINOIS, AssIGNoR TosurER-DIESRLTRACTOR CORPORATION, OF LA PORTE, INDIANA, A CORPORATION OF NEW YORK.

ATOMIZER SPRING.

In injection valves for oil engines it is, among other things, desirableto provide exceedingly minute openings through which a liquid fuel, onits way to the combust1on zone, may be forced in order to secure therequisite atomization and velocity and I have found that in order-to prouce the most satisfactory results, it is desirable that Y the valveopening be so minute as to be measured in terms of ten-thousandths of aninch.

The prior art, at the present time, shows development along the line ofspring-seated or spring-closed valves, wherein the valve opening foratomization and injection ismeasured in terms not of ten-thousandths,

but of one-thousandths OI' an inch, and the reason for this is that thenormal type of helical, cantilever and beam spring 1s not adapted togive the necessary minute openings. i

I have found the. difliculty of normal essential to use a spring havinga highcharacteristic.

F or the purpose of the present invention, I have taken the expressionspring characteristic to mean the load-defiection ratio. Referring tosuch classification, in Fig. 1 of the drawings, conventional springforms are represented generally by the line which shows largelyincreased deflection for a given' increase in load. The type of springaction used to secure ,exceedingly small valve openings is indicatedgenerally by the line Y, in which increases in deflection are very smallfor the same given in.- creases in load.

It is a fact, that compared with other ordinary commercial spring forms,the springs used at the present t1me in connection with spray valveshave a comparatively high characteristic. However, by comparison withwhat is necessary to give the desired small openings in the valve, theyhave a very low characteristic.

In order to point out the peculiar qualities of my spring, I shalldiscuss spring designs witlr particular reference to theratio of massdeformation to total deflection. lhat'is, the ratio of the distortion ofthe particles of the spring material to the detlection of the spring atthe point of lits maximum motion.

Deformation of spring material is of two general kinds. First, massdeformation, in which atheoretic infinitesimal unit is oonsidered andits change in shape under the application of load studied, and second,structural dellection of the spring. Structural deflection is the resultof multiplication of the mass deformation of. the infinitesimal units..

The term mass deformation is used herein to describe the deformation ofthe particles of the spring material. And for purposes ot' study ot'spring action, these particles are usually arbitrarily considered astiny cubes which are taken, in the development of the theory of springs,as units Whose action is to be studied and from whose combined actionsthe nature of spring deflection can be determined. For convenience,these units are Yusually considered ascubes. Load is appliedk to thelspring structure and `its elfect on one of these particles, situatedpossibly at some distance from the point of application of the load, isstudied. This little cubicparticle will be slightl flattened andthickened if the load acts in' irect compression. It will be slightlyelongated and thinned, if the load acts in tension. It will be twistedif the load acts in torsion. The

`effect of this change in sha-pe of this small vmultiplication as far aspossible, so that the deflection for a given distort-ion of a unitparticle will be very small in comparison with the other types ofspring. All normal spring forms are deliberately designed to get alarge, or as large as possible, a deliec-Y tion for a given distortionof the unit particle. In my design, I do the opposite, in

vthat I try to get as small a deliection as possible for a. givendistortion of the unit llO particle. Of course, the srt illest amountwould be a direct addition of the unit mass deformation.

One form of my spring, which is shown in Fig. 2 of the drawings, I havechosen to Call the straight wire spring. In the drawings the straightwire is designated by the letter E. rIhis form of spring ischaracterized by the least possible multiplication of mass distortion,and the ultimate deflection is actually the sum of the mass deformationof the particles of spring material.

Each small unit of the spring material stretches a very minute amountand the net effect at the end of the wire, where the valve head islocated, will be the arithmetical sum of these unit stretches.

In the common'cantilever spring familiar as an automobile spring, theunit, arbitrarily taken to be cubic, is distorted to rhomboidal form andthis distortion is not only multiplied by the length of the lever arm ofthe cantilever, but the distortion of the succeeding units, eachmultiplied by its lever arm, is also added, so that there is a verygreat structural deflection at the end of the spring for relatively veryslight changes in form ot the infinitesimal unit.

The type of multiplication of unit deformation resultant in structuraldeflection above described in connection with the cantilever spring, ispresent also in the helical and beam spring, and in all other generallyknown spring forms. And all such springs are designed particularly inorder to produce such multiplication. In contra-distinction to suchsprings, my spring is designed to reduce such multiplication of unitdistortion. It will be seen, therefore, that the intention in the designof my spring is dialnetrically the opposite of the intention in thedesign of customary spring types.

In a general way it can be said, therefore, that my type of spring takesadvantage of mass elasticity or the inherent elastic property ofsubstance and the structure is not so shaped or formed that the elasticdistortion is greatly multiplied and increased kinematically as innormal spring forms, but on the contrary, is particularly shaped so thatthe elastic deformation under given loads is as small as possible. Viththis type of structure which is used in the various forms of my valves,the opening caused by pressure as liquid is fed to the valve underseveral thousand pounds pressure, ranges from one-half of oneten-thousandth to fifteen ten-thousandths of an inch, and with normaloperation, two to four tenthousandths. This gives in the first place, anexceedingly minute opening which is necessary for atomization of liquidfuel to a degree comparable to that secured by air injection, second itassures that the opening will at no time during the injection cientlysmall to secure the desired atomization.

This type of spring action has the advantage over other forms ofmaintaining a tight joint between valve head Aand seat at all timesexcept during a carefully determined injection period and prevents withcertainty any dripping.

This typel of spring may be applied to injection valves in a number ofways and the location is more a matter of convenience and practicabilitythan a matter of change in the atomizing operation of the valve` In thevalve described, it Will be seen that the'elongation of a; straight wireis made to serve, the valve head being attached to the end of this wireand held firmly on its seat thereby, opening oniy when the hydraulicpressure is sufficient to overcome the initial tension and produceadditional elongation.

The principal point is that, in this type of spring when it is used in'conjunction with an injection valve, microscopic openings can be securedand these microscopic openings permit the breaking upof liquid fuel intoparticles approaching molecular dimensions of gas, and this degree ofatomization permits operation of oil engines with solid injectioncomparable to that formerly obtained only with air injection.

Another and perhaps more accurate way of stating the same situation isthat the exceedingly minute or microscopic openings I secure for theinjection of the fuel are in the l order of magnitude of the mean freepath of the molecules of the liquid fuel, and in fact the injectionopening which I propose Ato use may actually be made not more thanthirty times the mean free path under standard l lllfi valve. It isprovided with a central bore as shown and has adj ustably and removablypositioned within it a valve stem or tension member E which carries atits bottom an outwardly opening valve member El which is seated in theend of the spray valve housing. This housing is provided at its end witha reduced and outwardly threaded portion E2 which is fitted directlyinto the wall of the cylinder. At its upper end the stem E is' providedwith an enlargement which is threaded as at C?.

D is apacking surrounding the enlarged portion of the member E. D1 is agland screwed into place and compressing and holding the packing D inposition. This gland has a yoke D2 formed on it and preferably integralwith it. Within the yoke and positioned on thejthreaded portion C7 is ahand wheel D3. This wheel may be rotated so as to move the threadedportion Ce in and out and thus lto unseat and to seat valve E1 and varythe degree of tension with which it is held upon its seat.

B4 is a passageway communicating with the interior of the bore ofthevalve housing B, and B5 is an oil or fuel inlet duct by means of whichthe fuel or other liquid to be sprayed is fed from any suitable sourceand by any suitable means to the valve. Although I have shown in mydrawings an operative device, still many changes might be made in size,shape and arrangement of parts without departing materially from thespirit of my invention, and I wish, therefore7 my drawings be regardedas, in a sense, diagrammatic.- j

One characteristic of my spring form is that I relyI for my springaction on resistance of the spring material in tension unmultiplied byits kinematic structure so that any displacement is merely an arithmeticsumation of molecular distortion as contrasted .with normal spring formsWhich yield with bending or torsion and wherein the lever arm movementmultiplies greatly the molecular displacementand wherein bending ortorsion assume relatively greater importance with 'respect to tensionthan they do in the spring form that I have used.

l. In an atomizer having a discharge aperture, a closure, adapted to bedisplaced bv hydraulic pressure to permit fiow` throug the aperture,yielding means under adjustable initial tension, for resistingdisplacement of the closure, said means being adapted to resistdisplacement of the closure after the initial tension has been overcomelargely by the resistance of such means to mass deformation.v I

2. In a direct fuel injection system for interna] combustion engines, aninjection valve comprising a valve head and valve seat, a valve retainercomprising a metal rod rmly holding the valve head on its seat, andmeans for supplying liquid fuel to the valve under a pressuresufficiently high "to open the valve by elongating the said rod but wellwithin the limit of elasticity of the rod.

3. In a direct fuel injection system for internal combustion engines, aninjection valve comprising a valve head and valve seat, a valve retainercomprising a cold-drawn steel rod firmly holdingthe valve head on itsseat,

and means for supplying liquid fuel to thevalve under a pressuresufiiciently high to open the valve by elongating the said rod but wellwithin the limit of elasticity of the rod.

4Q In an injection valve for internal combustion engines adapted to burnliquidiuel, the combination of a'casing provided with a passa ewaythrough which fuel may be supplie a valve seat formed at the edge ofsaid passageway at one end of the casing, a

.' whereby the tension of the said rod may be adjusted.

5. In a system of direct fuel injection for internal combustion engines,an injection valve comprising a valve head and valve seat, a metallicvalve retainer firmly holding the valve closed, means for applyingliquid fuel to the valve head under a pressure suiiicient to effect theopening thereof against the resistance to linear deformation of themetal of the retainer but well within the limit of elasticity of themetal thereof, and means for adjusting the resistance to the opening ofsaid valve, substantially as described. Y

f5. In a system for atomizing liquids, anv atomizing valve comprisingavalve head and valve seat, a valve retainer comprising a metal rodfirmly holding the valve head on its seat and means for supplying liquidto the valve head under a pressure suiiicientlyy high to open the valveby elongating the said rod but well within the limit of elasticity ofthe rod.

Signed at Chicago, county of Cook, and State of Illinois, this 6th dayof August,

PHILIP LANE SCOTT.

